Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G7/00—Direction control systems for self-propelled missiles
  • F41G7/20—Direction control systems for self-propelled missiles based on continuous observation of target position
  • F41G7/22—Homing guidance systems
  • F41G7/2206—Homing guidance systems using a remote control station
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/30—Transforming light or analogous information into electric information
  • H04N5/33—Transforming infrared radiation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G3/00—Aiming or laying means
  • F41G3/14—Indirect aiming means
  • F41G3/145—Indirect aiming means using a target illuminator
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G3/00—Aiming or laying means
  • F41G3/02—Aiming or laying means using an independent line of sight
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G3/00—Aiming or laying means
  • F41G3/14—Indirect aiming means
  • F41G3/16—Sighting devices adapted for indirect laying of fire
  • F41G3/165—Sighting devices adapted for indirect laying of fire using a TV-monitor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G3/00—Aiming or laying means
  • F41G3/32—Devices for testing or checking
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
  • G01C21/005—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 with correlation of navigation data from several sources, e.g. map or contour matching
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
  • H04N5/445—Receiver circuitry for the reception of television signals according to analogue transmission standards for displaying additional information
  • H04N5/44504—Circuit details of the additional information generator, e.g. details of the character or graphics signal generator, overlay mixing circuits
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/18—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
  • H04N7/183—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast for receiving images from a single remote source

Definitions

• the present invention relates to an imaging instrument for controlling a target designation.
• the light spot produced by the beam on the target serves as a guiding mark for the craft: a detection system which is embedded in the self-guided craft detects the light spot, and a steering system of the The craft maintains its trajectory towards the light spot until the craft reaches the target.
• the accuracy of the impact of the self-guided craft on the target therefore directly depends on the precision with which the beam is directed and then maintained on the target. For this, imaging instruments are used, which make it possible to control in real time that the spot of the light beam is located on the target.
• Such instruments make it possible to simultaneously view the scene, for example an outside landscape, in which the target is located, for example a vehicle, and the light spot that is produced by the target designation beam, on the target or near the target. it.
• the direction of the target designation light beam can be corrected to return the spot more accurately to the target.
• the scene is imaged by the instrument using infrared radiation, for example within a wavelength range that ranges between 3 ⁇ (micrometer) and 15 ⁇ , and the radiation the target designation beam has a wavelength equal to 1, 06 ⁇ .
• the target designation radiation is then outside the spectral range of the radiation that is used to capture the scene as an image.
• the use of instruments using infrared radiation is necessary to obtain designation ranges that are important. We will speak in this case of long staves.
• NIR near infrared
• the NIR domain corresponds to the wavelength range which is between 0.8 ⁇ m and 1.5 ⁇ m.
• the ranges of systems that use these instruments are lower than those of systems using infrared radiation whose wavelength is between 3 pm and 15 ⁇ , and in this case we will speak of averages carried.
• the scene image and the spot of the target designation beam are captured with two image sensors, which are sensitive in two separate wavelength intervals. But then there is uncertainty as to the accuracy with which the images that are produced separately by the two sensors are then superimposed, so that an operator can accurately verify the location of the target designation spot inside. from the scene. Because of this, there is an important interest in having a target designation control instrument that uses a single sensor to capture the image of the scene and simultaneously display the target designation spot in that image. scene.
• the object of the invention is to improve the conditions and the reliability of the control of the designation of a target, when a control instrument is used which has only one image sensor.
• the object of the invention is to provide an image of the target designation spot using such an instrument, with a contrast and / or a signal-to-noise ratio which is (are) improved.
• the invention proposes a new imaging instrument for controlling a target designation, which comprises:
• an objective adapted to form an image of a scene with a first radiation, called natural radiation, which comes from elements of the scene, and adapted so that the image formed contains a contribution from a target which is contained in the scene, this contribution being produced by a second radiation, called pointing radiation, which is backscattered by the target; and a matrix image sensor, comprising pixels elements which are each responsive to natural radiation and pointing radiation simultaneously, the image sensor being arranged to capture the image formed by the lens.
• the instrument of the invention is of the single image sensor type as presented above.
• the image that is captured by the sensor is indeed a representation of the scene, in which the Natural Radiation and Pointing Radiation together help to bring up within the pictorial scene, the target that is illuminated by the radiation of pointing.
• the instrument further comprises:
• a filter which covers a limited zone of the image sensor, called the confirmation zone, and which is adapted to transmit to the pixel elements that are contained in this confirmation zone, selectively the pointing radiation excluding the natural radiation; or excluding a portion of the natural radiation that is spectrally separated from the pointing radiation.
• the target when the instrument is oriented towards the scene so that the target is imaged in the confirmation area of the image sensor, the target appears in the captured image only by the backscattered pointing radiation, or appears in the image captured primarily by this backscattered radiation, as long as the target is smaller than the confirmation area.
• this image of the spot appears on a black or dark background in the confirmation area, so that it has a contrast important, and so is very visible.
• the filter suppresses the photon noise of the natural radiation in the confirmation zone, so that only the photonic noise of the backscattered pointing radiation remains in this zone.
• the photonic noise of the backscattered pointing radiation is lower, typically at least four times lower, than the photon noise of the natural radiation in the scene image, so that the target designation spot appears much more clearly in the image. the confirmation area.
• this operator can move the optical line of sight of the instrument by rotating, to bring the image of the target into the confirmation area. he can then visualize the spot of the backscattered radiation radiation within the confirmation zone with a higher contrast and signal-to-noise ratio, and verify in this way with more certainty if this spot is located precisely on the target or offset from it.
• Such a displacement of the line of sight is called misalignment in the jargon of the skilled person, and is a maneuver that is particularly fast and simple for the operator, to control that the task of designation is precisely on the target.
• Such an instrument according to the invention can be adapted in particular so that the wavelength of the natural radiation which is detected by the pixel elements of the image sensor is comprised
• the wavelength of the pointing radiation which is also detected by the pixel elements of the image sensor is between 1.00 ⁇ and 1.10 ⁇ , being able to be equal more specifically to 1, 064 ⁇ ;
• the filter which covers the confirmation area of the image sensor may be an interference filter.
• this filter has a transmission spectral window which includes the wavelength of the pointing radiation, but which excludes natural radiation or at least part of it.
• the confirmation area, where the filter on the image sensor is located may be located near a peripheral edge of the array of pixel elements of the image sensor, or a corner of that array , or may be adjacent to this edge or die corner.
• the image of the scene that is captured by the image sensor may correspond to an optical input field having a first angular dimension of between 8 mrad (milliradian) and 80 mrad, and a second angular dimension of 6 mrad and 60 mrad, this second dimension being measured perpendicular to the first dimension.
• the filter may have dimensions such that it corresponds, through the lens, to a portion of the optical input field which has a third angular dimension of between 0.3 mrad and 3 mrad, when this third dimension is measured parallel to the first dimension of the optical input field, and which has a fourth dimension also between 0.3 mrad and 3 mrad, when this fourth dimension is measured parallel to the second dimension of the optical input field.
• the instrument may furthermore comprise:
• a reference system adapted to superimpose a sighting target on the image captured, at a location of this image which is determined with respect to the image sensor;
• a misalignment device adapted to turn the instrument by a fixed angle of depointment, so that an element of the scene which is imaged on the sighting target before a misalignment is initiated, becomes imaged in the area confirmation when the misalignment is done.
• the instrument may further comprise a harmonization system which is adapted to adjust a position of the sighting target with respect to the image sensor, so that the target is imaged at a center of the confirmation area.
• a harmonization system which is adapted to adjust a position of the sighting target with respect to the image sensor, so that the target is imaged at a center of the confirmation area.
• an imaging instrument for controlling the designation of a target which is in accordance with the invention, may be externally designated, that is to say that the beam of the pointing radiation to designate the target is produced by a source that is independent of the imaging instrument.
• the instrument is said internally designated when the source of the pointing radiation is part of the instrument, or is integral with it.
• the instrument then further comprises:
• a target designation system which comprises a laser unit adapted to produce a beam of pointing radiation, and which is oriented to send this beam of pointing radiation onto the target.
• the misalignment device can be adapted to jointly rotate the objective, the image sensor and the laser unit.
• the instrument can then further comprise a compensation system which is adapted to maintain the beam of the pointing radiation parallel to the optical line of sight of the lens and the image sensor both that the misalignment is not initiated, and to be effective once the misalignment is performed so as to compensate for an effect of the misalignment for the beam of the pointing radiation.
• the compensation system can include:
• a prismatic plate transparent for the beam of the pointing radiation, and with two flat faces which form between them a fixed dihedral angle;
• a movable mechanism that is adapted to introduce the prismatic blade into a path of the pointing beam of radiation when a misalignment is triggered, and to remove it when the misalignment is removed, or vice versa.
• the dihedral angle is then selected so that the prismatic blade produces, when introduced into the path of the pointing beam of radiation, a deflection of this beam which is opposite or identical to the angle of misalignment.
• Other misalignment devices are possible, such as translational devices of a lens orthogonal to its axis, or mirror angular deflection devices for optical components that are placed between the pointing system and the scene.
• a further aspect of the invention relates to a target designation control method, which comprises selectively designating the target in the scene using a pointing beam of radiation, and simultaneously viewing the scene with a spot of designation of the target that is produced by a backscattered portion of the pointing radiation, using an imaging instrument that is in accordance with the invention.
• FIG. 1 is an optical diagram of an imaging instrument according to the invention
• FIGS. 2 and 3 show a scene and a target as visualizable using the imaging instrument of FIG. 1; and FIGS. 4a and 4b illustrate an internally designated imaging instrument, in a central pointing position (FIG. 4a) and in a misalignment position (FIG. 4b).
• an imaging instrument 10 which is in accordance with the invention comprises an objective 1 and a matrix image sensor 2.
• a photosensitive surface S of the image sensor 2 is located in a focal plane of the objective 1, so that the objective 1 forms an image of a scene SC which is distant in front of the lens 1, on the image sensor 2.
• the instrument 10 is functional for a natural radiation denoted RN, and for a pointing radiation denoted RP.
• the natural radiation RN is emitted or diffused by elements of the scene SC which is comprised in an optical input field of the instrument 10.
• the natural radiation RN may be situated in the spectral range of visible light, which is between the wavelength values 0.360 ⁇ (micrometer) and 0.800 m, or even up to 1, 5 m.
• the natural radiation RN may be infrared radiation which is between the wavelength values 3 m and 15 ⁇ . Such natural infrared radiation allows diurnal and nocturnal visions of the SC scene.
• the pointing radiation RP may be laser radiation, for example at 1, 06 ⁇ . Such radiation is used to designate a TG target in the SC scene.
• the pointing radiation RP is then backscattered by a portion of an element of the scene SC on which it is directed. Part of the pointing radiation RP which is thus backscattered is collected by the lens 1, and forms the image of the scene element portion on the image sensor 2.
• the image that is captured by this sensor 2 comprises a first contribution, formed by the natural radiation RN, and a second contribution, formed by the pointing radiation RP and superimposed on the first contribution. More precisely, the second contribution is a spot of pointing radiation, which appears in the image at the scene SC where the beam of the pointing radiation is backscattered.
• backscattered and retro-reflected words are used equivalently in relation to pointing radiation, although the use of one or the other depends on the characteristics of specular reflection or diffuse reflection of the scene element that is illuminated by the pointing beam.
• the beam of the pointing radiation illuminates a desired target
• the spot of the pointing radiation which is then obtained in the image that is captured by the sensor 2 is called the target designation spot.
• the matrix image sensor 2 comprises a set of photosensitive elements, or pixel elements, which are arranged at intersections of rows and columns inside the surface S of the sensor.
• FIG. 2 shows an exemplary image that can be captured with the instrument 10.
• the image shows the elements of the scene SC, among which can be the target TG.
• the target TG is a vehicle in the example shown.
• the optical input field of the instrument 10 may have the angular dimensions of 35 mrad (milliradian) x 20 mrad, by way of example.
• beams of natural radiation RN or point radiation RP which are parallel to the optical axis of view of objective 1 and image sensor 2, converge towards a central point of the surface S of this image sensor.
• the vehicle which can constitute the target TG may be in the center of the image when the optical line of sight of the instrument 10 is directed towards this vehicle. From this position of the optical line of sight, a misalignment of the instrument 10 can make it possible to translate the scene SC and the target TG into the image that is captured, to bring the target TG into a predetermined area of the surface S of image sensor 2, denoted ZC.
• Such misalignment is designated DP in Figure 2.
• the zone ZC of the surface S of the image sensor 2 is provided with a filter 3 (FIG. 1), which selectively transmits the radiation of pointing RP with respect to the natural radiation RN when the pointing radiation RP and natural RN are spectrally separated.
• the filter 3 can selectively transmit the pointing radiation RP with respect to a main part of the natural radiation RN which is rejected by the filter 3, when the spectral range of the pointing radiation RP is included in that of the natural radiation RN.
• the filter 3 can be produced in a manner known to the person skilled in the art, in particular in the form of a multilayer stack when it is of the interferential type. Such achievements can be found in the many books and articles that are available about optical filters.
• the zone ZC which is called the confirmation zone for the reason that will be explained later, can have the angular dimensions 1 mrad x 1 mrad when measured in the same way as the optical input field. It is entirely covered by the filter 3, so that the part of the image that is captured by the sensor 2 in the zone ZC is exclusively or essentially formed by the pointing radiation RP.
• the dimensions of the zone ZC cover all the potential disharmonizations of the designation beam with respect to the instrument 10.
• the operator knows that the designation spot is in the zone ZC .
• this zone ZC is preferably not too wide, so as not to hide the environment that is close to the target, or even the edges of the target if it is not very small cut.
• FIG. 3 corresponds to FIG. 2 when the target TG is illuminated by a beam of the pointing radiation RP.
• a beam of pointing radiation RP is of the laser beam type.
• the backscattering of the pointing radiation RP by the target TG produces a contribution in the image in the form of an illumination spot SP which is locally superimposed on the scene SC.
• this spot SP may have a contrast and a signal-to-noise ratio which are low by relation to the image of the SC scene that is formed by the radiation natural RN. For this reason, it is shown in Figure 3 in dashed lines on the vehicle that constitutes the TG target.
• the DP misalignment brings the image of the vehicle into the zone ZC
• the natural radiation RN no longer produces an image of the scene SC or the target TG in this area
• the image of the spot SP point radiation RP remains.
• This image of the spot SP then has a contrast and a signal-to-noise ratio which are high in the zone ZC.
• the spot SP is now shown in solid line in this zone ZC ( Figure 3).
• the image that is displayed is thus constituted outside the zone ZC by the scene SC, and in the zone ZC by the spot SP of the pointing radiation RP which is backscattered on the vehicle. It thus allows an operator who visualizes this image to confirm that the target designation spot, SP, is correctly located relative to the rest of the SC scene, and therefore located on the desired target TG. For this reason, the zone ZC is called the confirmation zone.
• the confirmation zone ZC may be located in the surface S of the image sensor 2, in a location that does not cause any inconvenience to the operator to understand, interpret or inspect the image content.
• this place may be near an edge or a corner of the surface S, preferably in a part of this surface S which may be occupied by a representation of the sky in the case of an outdoor scene.
• the dashed squares indicate preferred positions that are also possible for the confirmation zone ZC in the surface S.
• FIG. 3 also shows a sighting pattern M which is superimposed on the image captured, for example in the center of the surface S of the image sensor 2.
• a superposition is currently performed electronically, on the image data which are read from the sensor 2, relative to the positions of the pixel elements in the surface S.
• the sighting target M may be at a central position inside the surface S.
• Such a sighting target M is particularly useful when the amplitude and the orientation of the misalignment DP are predetermined, in other words that the misalignment is automatic in the jargon of the skilled person.
• the operator then observes the scene SC which comprises the target TG via the instrument 10, orienting the instrument so that the target TG appears in the sighting target M, if possible in the center thereof. It then actuates the automatic misalignment, which automatically produces a translation of the image on the surface S of the sensor 2, such as the element of the scene SC which was located in the center of the sighting target M, that is to say - say the TG target if any, becomes located in the confirmation zone ZC.
• the image that is acquired when the misalignment is thus produced allows the operator to verify in real time the existence and the location of the beam of the pointing radiation RP with respect to the target TG.
• the amplitude and the orientation of the misalignment DP therefore depend on the position of the confirmation zone ZC in the surface S of the image sensor 2.
• the misalignment DP can be selected so that the variation of direction it produced in the optical input field of the instrument 10 corresponds to a displacement in the focal plane, from the center of the sighting target M to the center of the confirmation zone ZC.
• Offset devices that are designed to automatically apply predetermined misalignment and orientation misalignment are well known to those skilled in the art, so there is no need to re-describe them here.
• FIGS 4a and 4b illustrate a particular type of instruments according to the invention, said internal designation.
• An instrument of this type further comprises a target designation system, which produces the beam of the pointing radiation, denoted FRP.
• This target designation system incorporates in particular a laser unit 5, which produces the FRP beam.
• the target designation system is fixed relative to the objective 1 and the image sensor 2, for example within a common housing 6.
• the assembly can then be mounted on a variable orientation support 7, preferably a support with two axes of rotation.
• a support 7 can produce the misalignment DP mentioned above, including automatically on triggering by the operator.
• the instrument 10 may further comprise a compensation system which ensures that the DP misalignment does not alter the orientation of the FRP beam although the target designation system is driven by the rotation of the support 7 with the 1 and the image sensor 2.
• a compensation system it may comprise a prismatic plate 8 and a movement mechanism thereof, which is designated by the reference 9
• the moving mechanism 9, also called moving mechanism may be a lever that moves the prismatic blade 8 between two predetermined positions.
• the prismatic blade 8 does not affect the FRP beam before the misalignment (FIG. 4a), and when the DP misalignment is produced by tilting the housing 6 via the variable orientation support 7, the prismatic blade 8 is inserted in the path of the FRP beam ( Figure 4b).
• the prismatic blade is designed to compensate for exactly the effect of the tilting of the housing 6, so that the illumination spot SP of the FRP beam in the scene SC remains stationary between before triggering the DP misalignment and after it is produced.
• the dihedral angle of the prismatic plate 8, as well as its orientation are selected as a function of the amplitude and the angular orientation of the DP misalignment.
• the dihedral angle of the prismatic plate 8 and its orientation are thus selected to produce a deflection of the FRP beam which is opposite to the angular variation of the housing 6 during misalignment DP.
• the prismatic blade 8 can be effective for the FRP beam before the DP misalignment, but becomes ineffective when the DP misalignment is produced.
• the dihedral angle of the prismatic plate 8 and its orientation must be selected to produce a deflection of the FRP beam which is identical to the angular variation of the housing 6 during misalignment DP.
• imaging conditions are selected, such that the illumination spot SP of the pointing radiation RP is clearly visible inside and outside the confirmation zone ZC, in the image that is captured.
• the instrument 10 is then placed in the detented position, and a difference is measured in the captured image, between the center of the illumination spot SP and the center of the confirmation zone ZC, in the direction of the latter.
• the DP misalignment is then removed, so that the illumination spot SP returns towards the sighting target M in the newly captured image, but with a possible error with respect to the center thereof.
• the sighting target M is then displaced with respect to the sensor 2, from the new position of the illumination spot SP, with an oriented deviation which is equal to that which has previously been measured in the detented position.
• the sighting target M can be translated into the captured image at the same time and in the same way than the SC scene and the SP illuminance spot.
• the invention may be reproduced by adapting or modifying secondary aspects thereof with respect to the embodiments which have been described in detail above.
• the target designation system can be secured to a fixed part. of the misalignment device, so that the misalignment compensation system is no longer necessary.
• the invention can be applied to an imaging instrument for the externally designated target designation control, i.e., the imaging instrument is separate and independent of the designation system. target.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Remote Sensing (AREA)
• Multimedia (AREA)
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• Automation & Control Theory (AREA)
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• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Length Measuring Devices By Optical Means (AREA)
• Position Input By Displaying (AREA)
• Optical Radar Systems And Details Thereof (AREA)

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• 2017
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